Pharmacokinetic approaches applied to data sets from in vivo experiments on radiolabeled drugs and radiopharmaceuticals are increasingly recognized as helpful in understanding the behavior of radiolabels and their carriers. These approaches are often essential when combined with methods for the calculation of dosimetry in obtaining the results required by industry and by the F.D.A. for new radioactive drugs. However, many scientists using pharmacokinetics and dosimetry have had little formal training in these fields. This course is intended for those individuals and is structured to be of greatest benefit to those who require additional training in the design of pharmacokinetic experiments, in the construction of compartmental and physiological models, in the principles of dosimetric calculations and in the use of popular computer programs for modeling and dosimetry. This three-day course is unique in its emphasis on radiolabeled drugs and radiopharmaceuticals. Because it is directed at practitioners of radiopharmaceutical design and others employing radioactivity, emphasis will be on topics relevant to this field. In place of topics such as drug availability oral administration, and the relationship between drug concentrations and effects, the program will describe the use of data on radioactivity levels in normal tissues obtained by external quantitation and on the different chemical forms of radioactivity in plasma, urine and tissue homogenates. These subjects will constitute the first two days of the course and will be taught by Drs. SHD Jackson and A. Johnston, recognized authorities on pharmacokinetics who together taught an earlier course on this subject at this institution. The final day will be devoted to dosimetry and will be taught by Dr. B Wessels, also an authority in his field. After an introduction of basic principles, the results obtained earlier by pharmacokinetic modeling will be used to evaluate radiation doses. In both phases of the course, the students will perform their own evaluations in a computer laboratory using programs such as CON SAAM and MIRDOSE. We are unaware of any existing course remotely similar in goals or content. By being led through the entire process from pharmacokinetics and mathematical modeling of animal and patient data to the calculation of organ and whole body radiation doses, students would be in a position to apply these skills independently in their own research.